I'm an alumna of SSU - graduated in 1997. As of when I left, the groups were:
NPC
Alpha Gamma Delta
Alpha Xi Delta
Gamma Phi Beta
NIC
Delta Sigma Phi
Phi Delta Theta
Sigma Alpha Epsilon
Tau Kappa Epsilon
There were a few multi-cultural GLOs, too, but I'm not sure who's still around. I believe Delta Sig is no longer there, and there's a local sorority who is interested in extension.
The sororities are all around 60 members, and the fraternities varied from 30-50. Greek life definitely isn't huge there, but Greeks did/do have a presence (very active in student life, other campus orgs and activities, etc.). Sonoma does not have Greek housing, although many groups have "unofficial houses" off campus.
I loved my Sonoma experience!
